Did you know?

Click any word in a definition or example to find the entry for that word

free radical - definition and synonyms

Close

What are red words?

90% of the time, speakers of English use just 7,500 words in speech and writing. These words appear in red, and are graded with stars. One-star words are frequent, two-star words are more frequent, and three-star words are the most frequent.

Close

ThesaurusThesaurus

Thesaurus diagram

The thesaurus of synonyms and related words is fully integrated into the dictionary. Click on the thesaurus category heading under the button in an entry to see the synonyms and related words for that meaning.

more
noun [countable] science     free radical pronunciation in British English
Word Forms
Close
singularfree radical
pluralfree radicals
  1. a molecule that has an extra electron and can react very easily with other molecules. Free radicals sometimes form in the human body and can cause cancer.
BuzzWord

mic drop

the action of deliberately dropping your microphone at the end of a speech or performance to show you think it was so good that nothing better could follow it

BuzzWord Article

Open Dictionary

rhythmus

moving with rhythm, together as one

add a word

Blog

A must for anyone with an interest in the changing face of language. The Macmillan Dictionary blog explores English as it is spoken around the world today.

global English and language change from our blog
Macmillan learn live love play